Understanding oxygen-deficient La2CuO4-δperovskite activated peroxymonosulfate for bisphenol A degradation: The role of localized electron within oxygen vacancy

Abstract

An A2BO4-type oxygen-deficient perovskite (La2CuO4-δ, LCO), which owns a better low-temperature reducibility, more abundant oxygen vacancies (OVs) and surface oxygen species than the benchmark CuO oxide, was first applied in peroxymonosulfate (PMS) activation. At 0.7 g/L of LCO and 2 mM of PMS, more than 96 % of bisphenol A (BPA) was removed within 60 min over a wide pH range of 3.1 ‒ 9.1. The cycle of surface Cu(II)/Cu(I) redox couple and lattice oxygen (O2−)/O2 were responsible for PMS activation. Besides, the OVs with localized electrons may directly activate PMS through single electron transfer pathway to generate surface-bound hydroxyl radical (OH) and sulfate radical (SO4−), as well as less singlet oxygen (1O2) for BPA degradation. The evolution of OH, SO4− and 1O2 were revealed by EPR tests. Briefly, this study provides the mechanistic understanding of A2BO4-type perovskite in activation of PMS for water treatment.